TACHIDIUS. 19 



and also as regards the maxillar palp, of which, very 

 possibly, my figure may be inaccurate. 



Sul-family 2. TACHIDIINJI, BoecJc. 



The species belonging to this sub-family agree with 

 the Longipediints in having the first almost exactly like 

 the three following pairs of feet, adapted for swim- 

 ming and not for grasping, and in having all the 

 branches of the swimming feet 3-jointed ; the acces- 

 sory branch of the second antenna consists of one or 

 two joints and is mostly small; the second foot-jaw 

 forms a clawed hand and is adapted for prehension, 

 and the fifth foot consists usually of only one joint. 

 To this division belong the genera Tachidius, Euterpe, 

 and Robertsonia. 



Diagnosis of Genera of Tachidiince. 



Both ("2-jointed , Euterpe. 



branches j 



of first { 3-jointed; secondary fl -jointed Tachidius, 



pair of | branch of posterior < 

 feet (_ antenna (.2-jointed Robertsonia. 



Genus 5. TACHIDIUS, Lilljeborg (1853). 



Cephalothorax broad, and not distinctly separated 

 from the abdomen; head united with first thoracic 

 segment ; abdomen'in both sexes 5-jointed. Anterior 

 antennas (PI. XXXVII, fig. 4) very short, 7-jointed. 



